【作者】 严敏；

【导师】 陈安军；

【作者基本信息】 江南大学 ， 包装工程， 2013， 硕士

【摘要】 冲击作为产品在流通过程中物理损坏或功能失效的重要原因，是缓冲包装动力学研究的重点问题之一。本文以斜支承包装系统为研究对象，探究跌落工况下斜支承系统的动力学特性及破损评价方法，为产品的包装设计提供理论指导。本文的研究内容主要包括：建立了系统跌落工况下动力学方程。基于系统的几何非线性特征，利用牛顿定律建立运动微分方程，小振幅条件下，对系统动运动微分方程进行简化，得到系统的近似动力学方程。通过系统恢复力、系统刚度、系统响应及振动频率等参数比较分析，验证近似动力学方程的精确性与适用性。研究表明，当支承角大于700、跌落高度小于0.5m时，近似动力学方程可以代替精确方程，使得动力学分析得到简化。跌落工况下的振动特性的研究。为研究问题的普遍性，得到系统跌落冲击下的振动动力学方程，探讨了系统的振动特性，分析了初始速度、系统支承角对系统振动响应和振动频率的影响。研究表明，初始速度是影响系统响应的主要参数，随初始速度增加，系统位移及加速度响应增加；适当减小系统的支承角度可以使系统的加速度响应幅值减小，系统振动周期延长。建立了跌落冲击响应分析的变分迭代法。针对系统无量纲动力学方程，利用变分迭代理论，得到无量纲位移、无量纲加速度和系统响应频率的一阶近似解析解，与四阶龙格-库塔数值方法比较，研究结果表明，变分迭代法求解跌落工况下斜支承系统动力学可行，不仅可以得到解析解，而且求解精度高。并运用无量纲位移、无量纲加速度和系统响应频率的一阶近似解研究了斜支承包装系统的跌落冲击特性，探讨了跌落高度、系统支承角和系统阻尼比对冲击响应和响应频率的影响。研究表明，跌落高度是影响系统响应的主要参数，随跌落高度增加，系统位移及加速度响应增加；适当减小系统的支承角度可以使系统的加速度响应幅值减小，系统振动周期延长；合理的选择系统阻尼比也可以有效地降低位移及加速度响应幅值。斜支承系统跌落破损边界的研究。应用龙格-库塔数值分析方法，以系统特征参数、无量纲跌落冲击速度以及支承角或阻尼比为基本评价量，构建了系统的二维跌落破损边界曲线和三维跌落破损边界曲面，讨论了系统阻尼比、系统支承角以及系统特征参数等对跌落破损边界的影响。研究表明，系统特征参数、无量纲跌落冲击速度以及系统阻尼比对破损边界影响显著，系统存在最佳阻尼匹配，当系统阻尼比接近最佳值时，系统对产品具有良好的保护性能，降低系统的特征参数或减小系统支承角可改善对产品保护性能。更多还原

【Abstract】 The impact, as an important reason of physical damage or failure in the process ofcirculation, is one of the key problems of the cushion packaging dynamics research. Based onthe inclined support packaging system as the research object, the article explored dynamicscharacteristics of the inclined support system in the condition of dropping and damageevaluation methods, and provided theoretical guidance for the design of the packing of theproducts. In the paper, the research content mainly includes:Dynamics equation of the system in the condition of dropping was established. Based onthe geometric nonlinear characteristics of the system, the differential equation of motion wasestablished using Newton’s law and simplified under the condition of small amplitude.Eventually we got the approximate dynamic equation of the system. Through comparativeanalysis of the restoring force of the system、 system rigidity、system response and vibrationfrequency, we verified the accuracy and applicability of approximate dynamic equation. Theresearch shows the approximate dynamic equation can replace the precise equation wheninclined support angle is greater than70°and drop height is less than0.5m. It makes thedynamic analysis simplified.Vibration characteristics in the condition of dropping were studied. For the universalityof the problem of the study, dynamics equation of the vibration of the system under droppingimpact was obtained. The vibration characteristics of the system were discussed. Theinfluence of the initial speed and system supporting angle to vibration response of the systemand vibration frequency was analyzed. The research releases the initial speed is the mainparameters influencing the system response. Displacement and acceleration response of thesystem increase with the increase of initial velocity; appropriately reducing the perspective ofsupporting system can make the amplitude of the acceleration response of the system decreaseand system vibration cycle extend.The variation iteration method of the drop impact response analysis was established. Inview of dimensionless dynamics equation of the system, we got the first-order approximateanalytical solution of the dimensionless displacement, dimensionless acceleration andfrequency of system response by using the variation iteration theory. The solution comparedwith numerical solution of the fourth order Runge-Kutta. The results of the research indicatesolving the inclined support system dynamics under the condition of dropping is feasible byusing variation iteration method. It not only can get the analytical solution and high precision.Using the first-order approximate analytical solution of dimensionless displacement、dimensionless acceleration and frequency of system response studied the impactcharacteristics of the inclined support packaging system and the influence of drop height、 supporting angle of system and damping ratio to impact response and frequency response.The research states drop height is an important parameter to affect the response of the system;the displacement and acceleration response of the system increase with the drop heightincrease; appropriately reducing the perspective of the system can make the amplitude of theacceleration response of the system decrease and system vibration cycle extend; reasonablechoice of system damping ratio can effectively reduce the displacement and accelerationresponse amplitude.Dropping damage boundary of the inclined support system was studied. Using numericalanalysis method and considering the parameters of the system characteristics、 thedimensionless velocity and supporting angle or damping ratio as the basic evaluationconstructed dropping damage boundary curves of the system or dropping damage boundarysurface. The effect of the damping ratio、system support angle and the parameters of thesystem characteristics on dropping damage boundary was discussed. The research reveals theparameters of the system characteristics、the dimensionless velocity and the damping ratiohave an obvious effect on dropping damage boundary. The system exists optimal dampingmatching. The system has good protection performance when damping ratio of the system isclose to the optimal value. Reducing the parameters of the system characteristics or systemsupporting angle can improve the protection performance.更多还原